Amid conflicting accounts, Iraqi and Kurdish commanders said Tuesday that they paused their advance on Mosul — a day after the start of a massive operation to retake ISIS’s last major stronghold in the country.

The front lines to the east of Mosul were largely quiet after US-led airstrikes and heavy artillery bombardments helped the Iraqi offensive aimed at retaking the embattled city.

“We are just holding our positions,” said Col. Khathar Sheikhan of the Kurdish forces known as the peshmerga, which captured several villages east of Mosul on Monday. “The Iraqi army will now advance past our arenas of control. We have achieved our objectives.”

But an Iraqi special forces commander said his troops have delayed an advance following a request from Kurdish forces for more time to achieve their goals.

It was not immediately possible to reconcile the conflicting accounts.

Brig. Gen. Haider Fadhil said his men had planned to move at dawn, but postponed the operation. He said Iraqi army and Kurdish commanders would meet later Tuesday.

Iraqi and Kurdish forces said Tuesday they had secured about 20 villages on the outskirts of the city in the first day of the operation, Reuters reported.

Iraqi Prime Minister Haider al-Abadi has vowed to liberate Iraq’s second-largest city from more than two years of rule by the jihadists.

Kurdish security forces take up a position as they fight overlooking the Islamic State-controlled in villages surrounding Mosul.AP

Abu Saif, a 47-year-old former company manager contacted by Agence France-Presse, said the streets felt eery as fighters and civilians both stayed indoors.

“The atmosphere in Mosul is strange, the sky is constantly black with smoke from tires Daesh (ISIS) lit everywhere,” he said Tuesday. “There is also the black smoke from the burning oil in the trenches Daesh dug around the city to hide their members’ movements.”

The battle for Mosul, which is expected to last weeks or months, will involve more than 25,000 troops, including the Iraqi army, the peshmerga, Sunni tribal fighters and Shiite militias.

A spokesman for the US-led coalition said the operation was proceeding as planned and that Iraqi forces were making “excellent progress.”

“There’s no pause in efforts to liberate Mosul. Troops are on the move on various axes of advance toward the city,” said Col. John Dorrian. “Some commanders have reached their objectives ahead of schedule after encountering light-to-moderate resistance.”

The Commander of the Joint Military Operation Commander, Army Lt. Gen. Talib Shaghati on Oct. 17AP

Complicating matters is the possibility that the extremists may use tens of thousands of Mosul residents as human shields to help hold onto the city, Thomas Weiss, the International Organization for Migration’s Iraq chief, told Reuters on Tuesday.

“Tens of thousands of people may be forcibly expelled, they will be getting trapped between fighting lines under siege, they may be even held as human shields,” he said.

Weiss also said there has been some evidence that ISIS might be using chemical weapons.

“Children, the elderly, disabled, will be particularly vulnerable,” he said. “In the United Nations country team, we believe that the Mosul situation has the potential to be one of the worst-case scenarios, expected to be the largest and most complex humanitarian operation in the world in 2017.”

The International Committee of the Red Cross appealed to all sides Tuesday to show humanity on the battlefield and spare the 1.5 million civilians in Mosul.

Robert Mardini, the ICRC regional director, said the agency had reminded the Iraqi government, Kurdish authorities and coalition forces of their duties under international humanitarian law.

It had not yet managed to address the “basic rules of war”with ISIS.

“But our ambition, and we will do everything we can, (is) to establish dialogue with this group because it is holding the city of Mosul and we absolutely need to have this dialogue kick-started. So all what I can say now is we will continue to try and try harder,” Mardini said.

Meanwhile, the Iraqi Army’s 9th Division reached the outskirts of the town of al-Hamdaniyah, south of Mosul, but stopped advancing because of snipers and suicide bombers, officials said.

By the end of the day Monday, Kurdish forces had retaken some 80 square miles), said Massoud Barzani, president of Iraq’s largely autonomous Kurdish region.

Peshmerga commanders on the ground estimated they retook nine villages and pushed the front line with ISIS back five miles. The front line east of Mosul is now about 20 miles from the city.